Impulse transmitting device



p 5, 1939- T. o. WESTHAFER ET AL 2,172,231

IMPULSE TRANSMITTING DEVICE Filed Jan. 6, 1938 Patented Sept. 5, 1939 UNITED- STATES PATENT OFFICE IMPULSE TRANSMITTING DEVICE Application January 6, 1938, Serial No. 183,628

7 Claims.

This invention relates to impulse transmitting devices and more particularly to impulse transmitting devices for use in the calling dials of automatic telephone systems,

It is an object of the present invention to provide a simple, rugged impulse transmitting device which is quiet in its operation.

In accordance with one embodiment of the invention, there is provided a contact controlling pawl adapted to be operated by projections on a camming wheel operable under control of the dial of an automatic telephone transmitting system, which pawl is pivotally mounted and has a spring attached thereto and to an extending arm of a lever pivoted on the same center as the pawl for normally tending to hold the pawl in either of two predetermined positions, depending upon the direction in which the pawl is moved. The arm to Which the pawl holding spring is attached is provided with means for limiting the amount of movement of the arm in two directions whereby the two predetermined positions are determined.

A better understanding of the invention will be had by reference to the following detailed description when considered in conjunction with the accompanying drawing, wherein Fig. 1 is a front elevational view of a telephone dialing mechanism, parts being broken away to show more clearly the details of construction of the present invention;

Fig. 2 is a rear view of the apparatus disclosed in Fig. 1;

Figs. 3, 4 and 5 are fragmentary elevational views of a portion of the apparatus shown in Fig. 1; and

Fig. 6 is a sectional view taken on the line 66 of Fig. 3 in the direction of the arrows.

Referring now to the drawing, wherein like reference numerals designate the same parts throughout the several views, the numeral I designates a dial for use in automatic telephone transmitting apparatus provided with a series of finger apertures l l, whereby the dial may be rotated in a clockwise direction until the finger of the first operating dial engages a stop E2, The dial is of the type common to telephone dialing apparatus, and upon its release, will be driven in a counter-clockwise direction by a spring motor (not shown), a suitable governor l3 being provided for controlling the speed of the dial in its return to normal position. The dial I0 is secured to a shaft M by means of a nut 15 threaded onto the end of the shaft. Carried by the shaft I4 is an impulse wheel or cam wheel l6 having one wide tooth l1 and a series of ten small teeth I 8 formed about its periphery. The stop I2 is fixed to a cup-shaped casing 2| ,which encloses the operating parts of the dialing mechanism. This mechanism includes an abutment 22 against which the spring motor (not shown) will urge a stop member 23 fixed to the shaft l4. The apparatus thus far described is the apparatus common to telephone dials in general use at the present time for actuating an impulse transmitter to send impulses for indicating the telephone number to which it is desired to be connected. In accordance with the present invention, a pawl, designated generally by the numeral 23, is adapted to be actuated by the teeth l8 or cam wheel or impulse wheel I6 and having a portion 24 thereof which extends into the path of the teeth l8 around the cam wheel I6 so that during the rotation of the cam wheel the teeth l8 will move the pawl 23, which is pivotally mounted between a bracket 25 secured to the casing 2| by screws 26 and a bracket 21 formed integrally with the casing 2|. The pawl 23 is fixed to a pivot pin 28, which is mounted in apertures 30 and 3! formed in the brackets 21 and 25, respectively. A portion 33 of the pawl 23 extends to the rear portion of the casing 2i and carries a tubular insulator 34 on a reduced portion 35 thereof, which, when the dial it is moved in a clockwise direction (Fig. 1) will be moved away from a contact spring 3'! normally engaging a fixed contact 38. Both the contact spring 3'! and fixed contact 38 form part of a spring pile-up 39, which controls the transmission of impulses for connecting a telephone subscriber with another subscriber through automatic or semi-automatic exchange. The operation of those springs in the pile-up 38 other than the contact spring 31 and fixed contact; 38 does not relate to the present invention and a detailed description thereof accordingly will not be given.

Upon the rotation of the cam wheel l6 and dial II in a counter-clockwise direction (Fig. 1), the portion 24 of the pawl 23 will be moved by each of the teeth I8 which had been moved past it during the clockwise rotation of the dial to cause the insulator 34 to break the contact between spring 37 and fixed contact 38 each time a tooth I8 passes under the portion 24 of the pawl. The portions 49 and 4| of the pawl 23 are bent over at right angles to the main body of the pawl for receiving the pin 28 and the portion 4| has extending therefrom an arm 43 to which a coil spring 44 is secured. The coil spring 44 has its other end connected to a lever 45 which is pivotally mounted upon the pin 28 and which is provided with a pair of depending arms 46 and 41 adapted to engage opposite sides of the bracket 25 to limit the movement of the lever 45 about the pin 28.

In the operation of the dialing mechanism to select a number, the dial It! may be moved manually in a clockwise direction to bring the edge of one of the apertures ll into alignment with the stop l2, whereupon the dialmay be released and will be returned to normal position, as shown in Fig. 1. During the clockwise rotation of the dial H, the camming wheel It will also move in a clockwise direction, and as the first tooth l8 en gages with the portion 24 of the pawl 23, the pawl and the lever 44 will be rocked from the position shown in Fig. 3 to the position shown in Fig. i, where the arm 45 will engage with the side of the bracket 25 and will thus be restrained from further movement in a counterclockwise direction. However, as the cam wheel is moved further, the pawl 23 will be rocked further against the tension of the spring 44. This latter movement obviously will be slight and as the portion 25 of the pawl passes over the first tooth l8 and the succeeding teeth IS, the spring M will move the pawl back a short distance to the position shown in Fig. 4:, but will not cause the pawl to slap sharply against the next succeeding tooth l8, thereby materially reducing the amount of noise made by the dialing mechanism during the clockwise rotation of the dial Hi.

When the dial H1 is released, the spring motor (not shown) will rotate it in a counter-clockwise direction, and as the first tooth l8 engages the portion 24 of the pawl 23, the pawl and lever 45 will be moved to the position shown in Fig. 5, where the arm Q6 will engage the bracket 25. Continued movement of the cam wheel IS in a counter-clockwise direction will move the pawl 23 against the tension of the spring 54 and the energy stored in the contact spring 31, for in the movement of the pawl 23 in a clockwise direction about its pivot, the portion 35 thereof carrying the insulator 34 will be moved into engagement with the contact spring 37 each time a tooth I8 strikes the pawl. The rotation of the cam wheel I6 back to its normal position will therefore cause the opening of the circuit between spring 31 and fixed contact 38 a number of times, dependent upon the number of teeth !8 which had been moved past the pawl during the rotation of the cam wheel [6 in a clockwise direction. It will be noted that during the return of the dial to normal position, at which time the selected number of impulses are transmitted by the breaking and making of the contact between the spring 31 and fixed contact 38, the portion 24 of the pawl will not be urged to snap back against a succeeding tooth l;8 after it has passed over a preceding tooth, thereby rendering the operation of the dialing mechanism comparatively silent.

Although a specific embodiment of the invention has been described hereinbefore, and a particular construction has been definitely described, it will be understood that adaptations and variations of the structure thus described may be made without departing from the scope of the appended claims.

What is claimed is:

1. In an impulse transmitting device, a rotatable finger wheel, a camming wheel fixed to the finger wheel, a pivoted pawl actuatable by said camming wheel, contacts operable by said pawl, and means for urging the pawl to remain in either of two predetermined positions, including a spring movable about the pawl axis.

2. In an impulse transmitter, a pair of impulse transmitting contacts, means for actuating one of said contacts to move it out of engagement with the other contact including a pawl, means for pivotally supporting said pawl, a spring attached to an end of said pawl, and a support for said spring pivotally mounted on the same axis as said pawl.

3. In. an impulse transmitter, a pair of impulse transmitting contacts, means for actuating one of said contacts to move it out of engagement with the other contact including a pawl, means for pivotally supporting said pawl, a spring attached to an end of said pawl, a support for said spring pivotally mounted on the same axis as said pawl, and means for limiting the amount of movement of said spring support.

4. In an impulse transmitter, a pawl having a cam engaging portion, a contact actuating portion and a spring engaging portion, a mounting for pivotally supporting said pawl, a lever pivoted on said mounting on the same axis as the pawl, and a spring connectedto said-lever and said pawl for holding the pawl in either of two predetermined positions.

5. In an impulse transmitting device, a camming wheel normally urged to remain in one position, a pawl associated with said camming wheel for actuation thereby, a pair of impulse transmitting contacts associated' with said pawl and adapted to be opened by said pawl during move- 7 ment thereof by the camming wheel in one direction, means for pivotally supporting said pawl, a spring connected to said'pawl, and a lever connected to said spring and pivoted about the same axis asthe pawl. V

6. In an impulse transmitting device for automatic telephone systems, a manually actuated dial, a disc secured to said dial and having a series of camming projections formed thereon, a pawl associated with said disc and adapted to be actuated by said camming projections, a support for pivotally supporting said pawl, a lever mounted on said support and pivoted on the same axis as the pawl, a spring interconnecting one end of said lever and said pawl, and a pair of stops on said lever for engaging the support to limit the movement. of the lever in either of twodirections for holding the pawl in position to be engaged by the camming projections during rotation of the disc.

'7. In a telephone dialing apparatus, a rotatable disc having a plurality of camming projections thereon, .a pawl supporting member, a pawl pivot.-

ally mounted in said supporting member, a lever pivoted on said supporting member, a spring interconnecting an end of the lever and a portion of the pawl for urging the pawl to remain in a predetermined position with respect to the lever, and a pair of stops on the lever for limiting'the movement of the lever about its pivot.

TERRENCE O. WESTHAFER. DAN J. DIEKMANN. 

